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Bicarbonate (HCO₃⁻) concentration in serum/plasma

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of bicarbonate, a key chemical in your blood that helps regulate acidity (pH) and supports normal breathing and kidney function.

Quick summary

["Your blood bicarbonate level helps balance acidity and supports overall health."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
54360-3
Short code
HCO3 Prt-sCnc
Synonyms
HCO3 Prt-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
28
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms like shortness of breath, fatigue, or signs of metabolic issues (e.g., too much acid or base in your blood). It may also be checked during evaluations for conditions like kidney disease, heart problems, or acid-base imbalances.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for a few hours if your blood is drawn early in the morning. Bring your medical records or recent test results if requested.

How the Test Works

A small blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed to measure bicarbonate levels using a specialized method that detects its chemical concentration.

What the Results Mean

Results are compared to standard ranges, but exact values can vary by lab. Low bicarbonate may indicate metabolic alkalosis (too much base), while high levels may suggest metabolic acidosis (too much acid). Your provider will discuss your specific results in the context of your health.

Reference range

NCBI: HCO3- 22-28 mmol/LN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Serum bicarbonate level

Frequently asked questions

What Does This Test Detect or Assess?
This test helps diagnose and monitor conditions affecting acid-base balance, such as kidney disorders, respiratory issues, or metabolic disorders. It also supports the evaluation of conditions like diabetic ketoacidosis, liver disease, or certain heart conditions.
How Often Should I Get This Test?
Your provider will determine how often you need this test based on your health status, symptoms, or ongoing treatment. Regular monitoring may be needed if you have chronic conditions like kidney disease or heart failure.
Can I Make Changes to My Diet Before the Test?
Generally, no dietary restrictions are required unless your provider specifies otherwise. However, avoid excessive intake of alkaline substances (like antacids) or certain medications that may affect bicarbonate levels for a few days before testing.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy